Quick Reference: Best Practice Settings
This serves as a quick reference for VMware vSphere ESXi hosts that are integrated with a Pure Storage FlashArray.
For additional in-depth information surrounding best practices please refer to Pure Storage KB: Web Guide: FlashArray VMware Best Practices.
Best Practices for ALL versions of ESXi
ESXi Parameters | Recommended | Default | Description |
---|---|---|---|
HardwareAcceleratedInit |
1 |
1 |
Enables and controls use of Block Same (WRITESAME). |
HardwareAcceleratedMove |
1 |
1 |
Enables and controls use of XCOPY. |
VMFS3.HardwareAcceleratedLocking |
1 |
1 |
Enables and controls the use of Atomic Test & Set (ATS). |
iSCSI Login Timeout |
30 |
5 |
Ensures iSCSI sessions survive controller reboots. |
TCP Delayed ACK (iSCSI) | Disabled | Enabled | Improves performance when disabled in congested networks |
Jumbo Frames (Optional)
|
9000 | 1500 | If you have a workload that would benefit from Jumbo Frames, and a network that supports it, then this is the recommended configuration. Otherwise, utilize 1500 to reduce complexity in configuration. |
HBA Queue Depth Limits | Default | Varies by vendor | Default is recommended unless specifically requested by Pure Storage due to high-performance workloads. |
VMware Tools |
Install |
Not Installed |
VMware paravirtual driver, clock sync, increased disk timeouts, and graphic support are part of the tools hence it is a crucial step. |
VM Virtual SCSI Adapter | Paravirtual | Varies by OS type | Not required to be changed, but for high-performance requirements, PVSCSI is required to be used. |
Network Time Protocol (NTP) | Enabled | Disabled | Enabling NTP is recommended for more efficient troubleshooting. |
Remote Syslog Server | Enabled | Disabled | Configuring a remote syslog server is recommended to ensure logging required for troubleshooting is available. |
It is also a best practice to set the "ESXi host personality" on the FlashArray for all ESXi host objects. This is described in detail in: FlashArray Configuration - Setting the FlashArray ESXi host Personality section. Please ensure this is applied whenever possible.
Best Practices specific to ESXi 5.x
ESXi Parameters | Recommended | Default | Description |
---|---|---|---|
DSNRO / Number of outstanding IOs | 32 | 32 | Default is recommended unless specifically requested by Pure Storage due to high-performance workloads. |
Path Selection Policy | Round Robin | MRU | Path Selection Policy for FC and iSCSI. |
IO Operations Limit (Path Switching) | 1 | 1000 | How many I/Os until ESXi switches to another path for a volume. |
VMFS Version | 5 | 5 | Please upgrade if any VMFS-3 datastores are in use. |
UNMAP Block Count | 1% of free VMFS space or less | 200 | Please refer to the VAAI or Best Practices document for additional information. |
Disk.SchedNumReqOutstanding (DSNRO) is the same as "Number of outstanding IOs". The difference is that it changed from a host level configuration (Disk.SchedNumReqOutstanding) to a per volume level (Number of outstanding IOs) in ESXi 5.5 and later.
You can read the VMware KB Article: Setting the Maximum Outstanding Disk Requests for Virtual Machines for additional information around this.
Best Practices specific to ESXi 6.x and ESXi 7.x+
ESXi Parameters | Recommended | Default | Description |
---|---|---|---|
EnableBlockDelete | 1 | 0 | Provides end-to-end in guest support for space reclamation (UNMAP). Only applicable to VMFS-5. |
Number of outstanding IOs |
32 | 32 | Default is recommended unless specifically requested by Pure Storage due to high-performance workloads. |
Path Selection Policy | Round Robin | MRU | Path Selection Policy for FC and iSCSI. |
Latency Based PSP (ESXi 7.0+) |
samplingCycles - 16 |
samplingCycles - 16 latencyEvalTime - 180000 ms |
How often a path is evaluated (every 3 minutes) and how many I/Os to sample (16) during the evaluation. |
IO Operations Limit (ESXi 6.0 - 6.7) |
1 | 1000 | How many I/Os until ESXi switches to another path for a volume. |
VMFS Version | 6 | 5 | Use VMFS-6 on vSphere 6.5 and later. |
If vSphere 6.7U1 or later are in use then you can use the VMW_PSP_RR module set to "latency" rather than IO Operations set to 1. In vSphere 7.0 and later, you should use VMW_PSP_RR module set to "latency". Please refer here for more information on Enhanced Round Robin Load Balancing and here for more details on why Pure recommends this change.